Inkjet printers are particularly effective at rendering high quality color images by using numerous small nozzles on a printhead to spray drops of liquid ink directly onto paper as the printhead traverses the paper. Inkjet printers typically include one of two types of ink ejection mechanisms to expel ink from a printhead to form a desired image—thermal bubbles or piezo-electric technology. In a thermal bubble inkjet system small heating elements, such as resistors, are heated to vaporize a small amount of ink to create a bubble. As the bubble expands, a small amount of ink is ejected from a nozzle associated with the heating element. Each inkjet printhead may contain hundreds of nozzles individually actuated to fire ink droplets. By selectively energizing heating elements as a printhead traverses a paper, the ink is expelled in a pattern to form a desired image. Piezoelectric systems achieve control of each printhead nozzle using a piezoelectric element instead of a heating element. Electric current applied to piezo crystals causes the crystals to vibrate, forcing a small amount of ink out of a nozzle.
Regardless of the inkjet ejection mechanisms used to expel ink from a printhead to form an image, the generation of high quality images requires, in part, that printheads handle multiple colors while generating a small ink drop mass to effect high resolution images. Although conventional inkjet printers used only three colors to generate images, today's inkjet printers may use eight or more colors to enrich the color table and accuracy of a printed image. The increasing number of colors presents a challenge to conventional ink delivery systems. These systems include disposable inkjet printheads having a single piece ink container, on-carrier systems having a printhead carrier that is separate from a replaceable ink chamber, and off-carrier systems where a printhead carrier is connected to a separated ink chamber by a tubing system.
Conventional disposable inkjet printheads are limited to four ink chambers (i.e., four colors) in a single piece body due to molding and tooling design constraints. Unless two disposal printheads are used in such a system, only on-carrier or off-carrier systems are able to accommodate more than four inks at a time. Unfortunately, current on-carrier systems require a manifold with ink flow channels between the ink chambers and the printhead to provide a passage of the ink to the printhead. The complexity and length of ink flow channels increases as the number of ink chambers increase and are positioned further from the ink ejection mechanism. This may lead to pressure drops of the ink in each ink flow channel, which may affect the feeding rate of the ink to the printhead resulting in poor jetting efficiency or ink starvation in the printhead. Therefore, what is needed is an on-carrier ink delivery system that permits the use of multiple ink chambers while minimizing and balancing the unequal length of ink flow channels.